Your thoughts on the enormous new hole in my bumper.
#141
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I'd be willing to bet that if you did nothing more than put a big ******* fan on that radiator the engine would never overheat. You don't believe this though. But it's the ******* truth. A big 25 or 30A fan will pull so much ******* air through that radiator the car will lurch forward at a red light when it comes on....
Or if you did the shrouding like I showed it wouldn't overheat with stock fans. IMO, adding scoopers and ducts to get more air to the front is a joke. There's plenty of area up there for all the air you need. You don't race at 3 mph. Most of the air that hits the front of the car doesn't go through the mouth. It goes around it. Putting a bigger opening won't do ****. Putting a scooper won't do ****. You have to do things to make air flow. Pressure building up in the engine bay doesn't help flow through the heat exchanger. So adding 4 times more frontal area to the mouth just causes more air to built up under the hood.
Or if you did the shrouding like I showed it wouldn't overheat with stock fans. IMO, adding scoopers and ducts to get more air to the front is a joke. There's plenty of area up there for all the air you need. You don't race at 3 mph. Most of the air that hits the front of the car doesn't go through the mouth. It goes around it. Putting a bigger opening won't do ****. Putting a scooper won't do ****. You have to do things to make air flow. Pressure building up in the engine bay doesn't help flow through the heat exchanger. So adding 4 times more frontal area to the mouth just causes more air to built up under the hood.
#142
I'd be willing to bet that if you did nothing more than put a big ******* fan on that radiator the engine would never overheat. You don't believe this though. But it's the ******* truth. A big 25 or 30A fan will pull so much ******* air through that radiator the car will lurch forward at a red light when it comes on....
Or if you did the shrouding like I showed it wouldn't overheat with stock fans. IMO, adding scoopers and ducts to get more air to the front is a joke. There's plenty of area up there for all the air you need. You don't race at 3 mph. Most of the air that hits the front of the car doesn't go through the mouth. It goes around it. Putting a bigger opening won't do ****. Putting a scooper won't do ****. You have to do things to make air flow. Pressure building up in the engine bay doesn't help flow through the heat exchanger. So adding 4 times more frontal area to the mouth just causes more air to built up under the hood.
Or if you did the shrouding like I showed it wouldn't overheat with stock fans. IMO, adding scoopers and ducts to get more air to the front is a joke. There's plenty of area up there for all the air you need. You don't race at 3 mph. Most of the air that hits the front of the car doesn't go through the mouth. It goes around it. Putting a bigger opening won't do ****. Putting a scooper won't do ****. You have to do things to make air flow. Pressure building up in the engine bay doesn't help flow through the heat exchanger. So adding 4 times more frontal area to the mouth just causes more air to built up under the hood.
#143
You can get an idea of how well your system works on the streets. It's not the same, but it will give you an idea. Like right now if I'm idling and the fans come on, they run 30-40 seconds before they go off. Before I sealed an IC and condenser to the front of the radiator they only ran 25-30 seconds before they kicked off, that's with a 5* hysteresis. I obviously hurt flow some at idle. BUT, the fans run less when at cruise.... Now, say I put a huge 25 or 30A fan. Now when when the fans come on they'd probably run 10 or 15 seconds and kick off. This would give you a VERY good idea of how much better your setup is as this shows the rate of heat transfer out of the radiator has improved substantially. And cost you nothing to test other than the cost of the parts, which is a given.
Last edited by patsmx5; 02-25-2009 at 02:18 AM.
#144
So what you're actually saying is that Begi is wrong with air scoopers and all aerophysics is disproven and all the aftermarket bumpers from amemiya, aizawa, garage vary, any shop or racecar that used or made functional parts with larger ducting area are wasting time?
A fan will spin and create a pressure differential across the heat exchanger, causing air to flow.
Id say keeping air from getting under the hood will help air flow through the heat exchangers much more than adding frontal area. As hustler mentioned before, he's seen where the hood will bulge at speed from air building up under the hood.
#146
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Well now I think that that miata looks fantastic.. only gripe I would have is that the design of the NACA duct is wasted there as the airflow hits it directly instead of passing over it, but the fact that it is a NACA duct doesn't mean it works any less well than any other shape hole there..
To pat - I agree that there are many parts out there which would appear to work a certain way but don't do as good of a job as one might hope in the real world, but when it comes to the frontal area of the car, a bigger opening to allow more air in will help given that as much work has been put into giving the air clean ways to get out as well.
Hustler - I would really focus on getting the air out of the engine bay and shrouding the entry so that the air entering does not get wasted. Also, the BEGI scooper is a good piece and should be installed - it will help. I agree with many here that I doubt it will be necessary for you to cut up the bumper for more air to get in. An extraction hood and a front splitter as well as shrouds from the bumper inlet to the IC/rad should really be everything you need and then some. I don't know if it is already in your plans but personally, for a track only car, I think it would be a huge mistake to not use some form of extraction hood.
-Ryan
To pat - I agree that there are many parts out there which would appear to work a certain way but don't do as good of a job as one might hope in the real world, but when it comes to the frontal area of the car, a bigger opening to allow more air in will help given that as much work has been put into giving the air clean ways to get out as well.
Hustler - I would really focus on getting the air out of the engine bay and shrouding the entry so that the air entering does not get wasted. Also, the BEGI scooper is a good piece and should be installed - it will help. I agree with many here that I doubt it will be necessary for you to cut up the bumper for more air to get in. An extraction hood and a front splitter as well as shrouds from the bumper inlet to the IC/rad should really be everything you need and then some. I don't know if it is already in your plans but personally, for a track only car, I think it would be a huge mistake to not use some form of extraction hood.
-Ryan
#147
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You can get an idea of how well your system works on the streets. It's not the same, but it will give you an idea. Like right now if I'm idling and the fans come on, they run 30-40 seconds before they go off. Before I sealed an IC and condenser to the front of the radiator they only ran 25-30 seconds before they kicked off, that's with a 5* hysteresis. I obviously hurt flow some at idle. BUT, the fans run less when at cruise.... Now, say I put a huge 25 or 30A fan. Now when when the fans come on they'd probably run 10 or 15 seconds and kick off. This would give you a VERY good idea of how much better your setup is as this shows the rate of heat transfer out of the radiator has improved substantially. And cost you nothing to test other than the cost of the parts, which is a given.
Driving on the street is NOWHERE near as abusive as track driving. My track toy runs perfect on the street, never turning on the fans. Track driving is a different story, 290* oil temps and 260* coolant temps. It sucks. And there is ducting in place and no thermostat....
#148
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Not at all.
Driving on the street is NOWHERE near as abusive as track driving. My track toy runs perfect on the street, never turning on the fans. Track driving is a different story, 290* oil temps and 260* coolant temps. It sucks. And there is ducting in place and no thermostat....
Driving on the street is NOWHERE near as abusive as track driving. My track toy runs perfect on the street, never turning on the fans. Track driving is a different story, 290* oil temps and 260* coolant temps. It sucks. And there is ducting in place and no thermostat....
P.S. Could you elaborate on what ducting is done, what vents/extractors are used, what radiator, if there is an IC, oil cooler, etc.? Thanks
#149
Well now I think that that miata looks fantastic.. only gripe I would have is that the design of the NACA duct is wasted there as the airflow hits it directly instead of passing over it, but the fact that it is a NACA duct doesn't mean it works any less well than any other shape hole there..
#150
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Not at all.
Driving on the street is NOWHERE near as abusive as track driving. My track toy runs perfect on the street, never turning on the fans. Track driving is a different story, 290* oil temps and 260* coolant temps. It sucks. And there is ducting in place and no thermostat....
Driving on the street is NOWHERE near as abusive as track driving. My track toy runs perfect on the street, never turning on the fans. Track driving is a different story, 290* oil temps and 260* coolant temps. It sucks. And there is ducting in place and no thermostat....
Try running one and watch what happens.
#151
Not at all.
Driving on the street is NOWHERE near as abusive as track driving. My track toy runs perfect on the street, never turning on the fans. Track driving is a different story, 290* oil temps and 260* coolant temps. It sucks. And there is ducting in place and no thermostat....
Driving on the street is NOWHERE near as abusive as track driving. My track toy runs perfect on the street, never turning on the fans. Track driving is a different story, 290* oil temps and 260* coolant temps. It sucks. And there is ducting in place and no thermostat....
No thermostat = Fail. Sorry, but that's a very poor decision to make. The thermostat is there for a reason. Without one you will get uneven cooling throughout the block.
#153
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I didn't say that driving on the street introduced as much heat into the cooling system as tracking the car, did I? Did you read my post? What I wrote was just a casual way to observe the rate of heat rejection out of the radiator when the fans come on. It's not necessarily a great test, but it's something.
No thermostat = Fail. Sorry, but that's a very poor decision to make. The thermostat is there for a reason. Without one you will get uneven cooling throughout the block.
No thermostat = Fail. Sorry, but that's a very poor decision to make. The thermostat is there for a reason. Without one you will get uneven cooling throughout the block.
Why is no thermostat failing? The thermostat is there to keep the car operating at a certain temperature on the street, where without one it would run too cold, especially on a cold winter night. BTW, this isn't on a Miata motor, but I'd still like an explanation of why no thermostat is so bad. I actually have one reason that I know of that it could be bad, but am not completely convinced it is true.
#154
I still don't buy that putting more frontal area up front is gonna magically force more air through a heat exchanger.
#155
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Increase the frontal area and you increase the pressure against the radiator. Ducting does the same thing, just more effectively (and with more effort). Pressure deltas are the name of the game.
#159
Why not. Pick one and why.